Commit 0c482772 authored by Pierre Ynard's avatar Pierre Ynard

youtube.lua: properly search for signature descrambling helper object

It is not anymore conveniently located before its use. Also, update look
up of descrambling rules.
parent 69c4ec60
......@@ -71,10 +71,13 @@ function buf_iter( s )
end
-- Helper to search and extract code from javascript stream
function js_extract( js, pattern )
function js_extract( js, pattern, alt )
js.i = 0 -- Reset to beginning
for line in buf_iter, js do
local ex = string.match( line, pattern )
if not ex and alt then
ex = string.match( line, alt )
end
if ex then
return ex
end
......@@ -95,18 +98,31 @@ function js_descramble( sig, js_url )
-- Look for the descrambler function's name
-- c&&a.set("signature",br(c));
local descrambler = js_extract( js, "%.set%(\"signature\",(.-)%(" )
local descrambler = js_extract( js, "%.set%(\"signature\",(.-)%(", nil )
if not descrambler then
return sig
end
-- Fetch the code of the descrambler function. The function is
-- conveniently preceded by the definition of a helper object
-- that it uses. Example:
-- var Fo={TR:function(a){a.reverse()},TU:function(a,b){var c=a[0];a[0]=a[b%a.length];a[b]=c},sH:function(a,b){a.splice(0,b)}};function Go(a){a=a.split("");Fo.sH(a,2);Fo.TU(a,28);Fo.TU(a,44);Fo.TU(a,26);Fo.TU(a,40);Fo.TU(a,64);Fo.TR(a,26);Fo.sH(a,1);return a.join("")};
local rules = js_extract( js, "function "..descrambler.."%([^)]*%){(.-)}" )
local transformations = js_extract( js, "var ..={(.-)};function "..descrambler.."%(" )
if not transformations or not rules then
-- Fetch the code of the descrambler function
-- var Go=function(a){a=a.split("");Fo.sH(a,2);Fo.TU(a,28);Fo.TU(a,44);Fo.TU(a,26);Fo.TU(a,40);Fo.TU(a,64);Fo.TR(a,26);Fo.sH(a,1);return a.join("")};
local rules = js_extract( js, "var "..descrambler.."=function%([^)]*%){(.-)};",
-- Legacy/alternate format
"function "..descrambler.."%([^)]*%){(.-)}" )
if not rules then
return sig
end
-- Get the name of the helper object providing transformation definitions
local helper = string.match( rules, ";(..)%...%(" )
if not helper then
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
return sig
end
-- Fetch the helper object code
-- var Fo={TR:function(a){a.reverse()},TU:function(a,b){var c=a[0];a[0]=a[b%a.length];a[b]=c},sH:function(a,b){a.splice(0,b)}};
local transformations = js_extract( js, "var "..helper.."={(.-)};", nil )
if not transformations then
return sig
end
......
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